1. Field of the Invention
The present invention relates to a control system for use in a filling system in an apparatus for filling liquid into containers such as bottles, cans or the like.
2. Description of the Prior Art
Filling apparatuses in the prior art employed means for controlling a filled amount of liquid based on estimates or approximations [Japanese Laid-Open Patent Specification No. 57-194989 (1982)].
Upon discharging surplus filled liquid from a bottle, a can or the like under suction or increased pressure, if the suction or the increased pressure is maintained nearly constant and if the amount of time allowed for discharge under suction or increased pressure is sufficiently long, then the filled amount (net amount) can be maintained nearly constant.
However, in the following situations, the time for discharging under suction or increased pressure will vary, resulting in unequal filled amounts (net amounts) or in the necessity of increasing the time set for filling, and in either case filling efficiency is degraded:
(1) when the pressure for discharging under suction or increased pressure varies;
(2) when it is desired to discharge under suction or increased pressure during a minimum period of time by means of a large number of nozzles; or
(3) when there is a fear that blocking may possibly occur in the nozzle for discharging under suction or increased pressure or that aging variation may possibly occur.